SMTP (Simple Mail Transfer Protocol) is the best option for sending emails from your Joomla install because it gives you the most control for sending according to best practices to ensure email deliverability, that is if your own mail sending is set up correctly (for more on that watch the video at • Email Deliverability for your Joomla ... )
Sending via SMTP is also a way to send bulk emails through a different email service if your web host restricts how many emails you can send. How to set up Joomla so it sends using SMTP is the topic of this Maintenance Monday live stream.